1. Field of Use
This invention pertains to an improved design for a valve port block and in particular an improved arrangement for the brake system of a hydrostatic loader.
2. History of the Prior Art
A review of the prior art failed to produce a particular arrangement as disclosed by the present invention. For example, U.S. Pat. No. 3,420,059 entitled "Fluid Motor Transmission and Improvements Therein", Van Wagenen et al., discloses a hydraulic motor arrangement (FIG. 4) wherein the motor shaft 25 carrying a cam 82 extends through an area in which a plurality of valve blocks 69 are mounted. However, the valve blocks appear to be individual units rather than a single unit with an opening extending therethrough for passage of the motor shaft.
U.S. Pat. No. 3,419,096 entitled "Low Friction Hydrostatic Transaxle", Zagotta, discloses a hydrostatic transaxle including a plurality of motors 34 and 36 and a manifold plate 78 but the motor shaft does not extend through the manifold plate. The pump shaft 60 appears to drive a port plate but does not extend through a valve block as disclosed in the present invention.
U.S. Pat. No. 3,800,901 entitled "Final Drive Decoupling and Parking Brake Arrangement for Hydrostatic Loader", Blomstrom et al., discloses a hydrostatic drive which includes a parking or emergency brake to effect the locking of the input side of the reduction gearing as driven by a motor shaft but does not seem to include the components or manner of attachment of the present invention.